Project Summary/Abstract Hemophilia A is a X-linked recessive bleeding disorder with genetic mutations of coagulation factor VIII (fVIII) gene, followed by a defect of fVIII in the patient?s plasma, and resulting in the failure of blood clotting. Replacement of therapeutic fVIII is currently applied as a therapy but ~30% of severe Hemophilia A patients suffer with the rise of anti-fVIII neutralizing antibody (fVIII inhibitor antibody), which blocks clotting activity of replaced fVIII in the plasma. Immune tolerance induction (ITI) or systemic immunosuppression by administration of high dose fVIII, or general immunosuppressive drugs, are currently standard treatments but these are very expensive and could cause adverse events (e.g., undesired systemic immunosuppression) compared to those prophylactic and therapeutic effects. Therefore, fVIII-specific clinical Treg cell therapy has been considered as an ideal alternative to control fVIII inhibitor antibody. Our team has demonstrated solid proof of concepts of Treg infusion therapy using fVIII-specific TCR (T cell receptor), CAR (chimeric antigen receptor), and BAR (B cell antibody receptor) Tregs. In this project, TeraImmune, in collaborations with the Scott lab and Dr. Michael Guerrera, will develop personalized clinical-grade fVIII TCR-Tregs using lentiviral gene transfer system. Furthermore, we will develop GMP ancillary materials (AMs) and related cGMP-compliant ex vivo manufacturing protocols for clinical-grade fVIII TCR-Tregs by combining of ODNps25 Treg stabilization technology.